Generally, the conventional boxes or cases of business cards or game cards have been designed and manufactured for the similar purpose, such that the cards are protected from being damaged or dog-eared when being carried in one's pocket. In these designs, the cases have a main body for holding the cards and a lid to cover the cards. When the index cards, such as the educational flash cards, are stored in a case, however, the conventional designs have a few serious shortcomings.
The major purpose of carrying the educational flash cards is to review repeatedly the contents written on the cards. A card is retrieved from the carrying case and returned into the case after being reviewed, and then the next card is retrieved and reviewed, in such a manner that all the flash cards in the case can be repeatedly reviewed in rotation. The conventional designs, however, have been inconvenient and inappropriate for this usage since, in those designs, all the cards had to be taken out of the case when only one card is to be grasped and reviewed at a time.
If the cards are held in a hand, the cards can easily get wet and disfigured by the perspiration from the palm. Some of the attempts to overcome this difficulty, which arises when only one card is sought to be grasped, can be found in the arts, as shown in U.S. Pat. No. 5,823,353 (Perrin et al.) and U.S. Pat. No. 5,452,793 (DiMeo, Jr., et al.). However, in all the prior-art designs of business card cases, the function of returning each reviewed flash card back to the carrier was not addressed at all, because it was not necessary to the business card cases.
Another important major feature that has been overlooked in the prior-art designs is an active locking device of the case. In the conventional designs the lid is kept with the main body by a passive means such as a tab or a groove which cannot securely lock the two pieces together. When the physically active teenagers use such a case for the educational flash cards, the case may be opened unintentionally or the tabs may be worn out by the repeated opening and closing of the carrier.